Steam-coolistg apparatus



Nov. 13 1928.

S. W. RUSHMORE STEAM COOLING APPARATUS Filed Aug. 10, 1926 INVENTOR 112mm"! Wfizamare Patented Nov. 13, 1928.

UNITED STATES SAMUEL W. RUSI-IMORE, OF PLAINFIELD, NEW JERSEY.

STEAM-COOLING APPARATUS.

Application filed August 10, 1526. Serial No. 128,343.

My present invention is related to that set forth in my companion applications, Ser. Nos. 128,344 and 128,345, in that it concerns cooling systems of the type commonly employed on automobiles or the like, but in which the heat transfer is mainly by boiling or superheating water 'to absorb surplus heat of the engine and condensing the resultant steam to dissipatesaid heat in the radiator. W In the present case, as in said applications and as in my prior Patent No. 1,378,724,-

granted May 17, 1921, the boiling may be brought about by having a force feed water circulating system of small heat radiating 1 capacity that serially includes the Water jacket, a conduit discharging into the base of the radiator and a pump drawing water from said base and force feeding it to the jacket, so that the core or large capacity radiating means is in shunt rather than series relation to the direct path of flow between the Water jacket discharge and the pump intake, in the base of the radiator.

In the present case, the boiling may be also brought about merely by limiting the-amount of water returned to the jacket and in such case the return may be cool water and there fore may be taken partly or wholly from the upper chamber of the radiator.

As in said companion applications, one of the objects of my present invention is to contrek the upflow of steam in the honeycomb by having the radiator full of water so as to submerge the cooling passages andcontrolling water circulation therethrough so as to control distribution and upflow of the steam and ensure practically noiseless condensation thereof in. the radiator tubes.

In said application, Ser. No, 128,345, the discharge is diffused so that the water circulation is mainly thermahbeing primarily induced by the down pressure of cold water in some of the tubes forcing up warmer water in other tubes and then accelerated by but controlling the steam flow.

In Ser. No. 128,344, the object is to es tablish a-forced water circulation by causing the discharge from the water jacket to operate in the lower chamber of the radiator, after the manner of an injector. The discharge being lengthwise of the lower chamoer, this forces water circulation upward in tubes in front of the: steam and water blast and down circulation in tubes in the reof, More and more of the steam in finely subdivided bubbles which partake of the forced circulation of the water and are practically dominated thereby, although the bubbles have a ballooning effect of their own due to the depth pressure.

While my present invention may be employed in connection with discharge arrangement of either of said companion applications, its object is to attain similar advantages of steam flow distribution in the upflow cooling passages, with noiseless condensation in said tubes, by flow resistances operating primarily to control the water circulation and through it the steamdistribution. Thus, my present invention involves control of hot fluid flow on principles generically similar to those included under the broader ciaims of my Reissue Patent No. 16,382, granted July 13, 1926. There is further similarity in that none of the tubes need be definitely determined as downflow tubes. All of the tubes may be free to becomeupflow, or part of them may be neutral, or downflow, according to what discharge device is used and according to varying conditions of steam evolution and radiator cooling rates.

A specific feature of considerable importance in my present invention is having the flow resistance distributed throughout the region of upfiow steam condensation within the tubes. So arranged it operates not only for distribution of the water flow, and subdivision of the steam, but also as a means for preventing high velocity movement of the water in the tubes and thereby surging in the upper chamber and objectionable noises in the tubes when the steam condenses by sudden collapse, as it is very apt to do under-certain conditions in ef'iciently cooled tubes.

Another specific feature of practical importance is the provision of distributed flow resistance devices, whereby ordinary commercial types of tubular radiator may be adapted for practice of my present inven tion, merely by opening the upper or lower chamber of the radiator and dropping one device in each tube, or in as many of the tubes as may be desired.

The above and other features of my invention will be more evident from the following description in connection with the accompanying drawings, in which n Fig. 1 is a side el vation convent onally lied to indicating my present sy.

Ull

Cit

an automobile engine and radiator, the radiator being shown in transverse section on the line 11, Fig. 2;

Fig. 2 is a vertical sectional view of the radiator, approximately on the line 22,

Fig. 1;

Figs. 3 and 4 are enlarged vertical and horizontal sectional views showing details of one of the cooling tubes with a flow-resistance device of the type indicated in Figs. 1 and 2, the view in F 3 being in section on the line 33, Fig. 2.

Figs. 5 and 6 are respectively similar views of a modification;

Figs. 7 and 8 similarly show another mot.- ification;

Fig.9 is like Fig. 3, but showing a difi'er ent type of flow resistance device; and

Fig. 10 is a diagrammatic view indicating a cellular type of hon ycomb having suitably distributed flow resistance.

In Fig. 1, the motor is conventionally indicated as including the usual crank case 1 and cylinder block 2, the upper parts of which are enclosed by waterjacket 3. The water cooling system is conventionally indicated as including the radiator l, located as usual, on the same level with the motor and directlyin front of it so that the lower part of the radiator is below the level of the water jacket of the motor. The circulation of the water from the bottom of the radiator is through a pipe 5 to pump 6, the

latter being preferably driven from the engine at directlyproportional speeds. The pump is indicated as being a gear pump, but this is merely to illustrate that the pump is one adapted to receive boiling water and force it into the water jaeket'against friction and any back pressure that may be caused by steaming. The pump discharges through apipe 7 into water jacket- 3, whence the path of flow is through riser outlet 8, and downwardly extending return pipe 9. Thepipe '4' may contain a eheck valve 10 to insure against back flow of water or steam such as might otherwise occur under operating conditions when the engine and pump are stopped. The return pipe 9 connects with a pipe 11, passing through the rear wall of the lower chamber of the radiator and discharging horizontally through an outlet 13.

The radiator is indicated as having the usual lower chamber 12 and upper chamber 15, serving headers for the intermediate core, indicated in this case as comprising a great multiplicityv of small tubes, there being in practice many more than indicated in the drawings. The up aer chamber is oreferabl orovided with an over flow inc 1 i 17 which preferably extends into the neck 18, which is closed by a filler cap 19. This overflow pipe is preferably freely opened to atmosphere, although it may be supplied with pressure sustaining breather val Yes as described in various of my prior patents and applications.

Ordinary motor vehicle radiators are characteristically thin from front to rear, usually 2 inches to 3 inches, and the core consists of tubes that are long and thin. the straight cylindrical types being, say inch to inch diameter, by 2O inches to 2slinches high. The core may be. say. 20 inches to inches wide. The usual fan. 20. is of diametersomewhat smaler than the width of the core and, being circular. naturally cools the middle tubes inu-th more than the sidetubes. Like the pump, it is preferably driven by the engine at prmortional speeds so that its cooling effectis variable.

So far as concerns appl cation of the broader principles of my invention to s tems such as above described, it is possible to use any of the discharge devices shown in my companion applications above referrml to, but as a basic feature of my present iuvention involves greatly increasing the flow resistances of the cooling tubes, there a definite advantage in employing the high velocity discharge devices of my applicationn Ser'. No. 128,344. Preferably, therefore. the jet 13 is located in one end of the lower chamber 12 and discharges horizontally be low the, bottom of most of the cooling tubes. Preferably, the nozzle is constricted to, say, inch diameter or less. The relatively small flow section results in imposing a substantial back pressure, which. may be se eral pounds in the water jacket, thereby raising the water jacket boiling point up to, say, 218 to 225, and with the further result that when large volumes of steam are evolved, the jet discharges at high velocity. Preferably, the nozzle discharges through a Venturi-like tube 13, whereby outside \vatrr in the rear of the tube is drawn in and propelled forward with the primary steam and water Such discharge operates to app y suction on some of the side tubes in the rear of the jet and pressure on all, of the other tubes in advance of the jet. This has the advantage that the passage most definitely determined as down-flow are near the side of the radiator wiere the tubes are less effectivcl'y cooled, thus leaving the more central tubes which are better. cooled by the direct draft of the fan, freer for invasion by the. upflow circulation. As in my prior application, the down tlow tubes in the rear of the jet maycut ell from the others by means of a transverse partition in the lower chamber, but in the present case this is not necessary.

l vhatever be the means for discharging the steam into the lower chamber, my pre ent invention, in its broader aspects concer the combination therewith of means having tendencies of its own independently of the tendencies of the discharge means for controlling, preferably toward equalizing, dis tribution of upflow among the several tubes and particularly for preventing high velocity flow in any of the tubes. To this end, the apparatus operates to maintain the lower chamber, cool tubes and upper chamber sub-' merged in water, thereby rendering the steam distribution and flow practically sul servientto water flow, and water flow resistances. In such a situation, flow resistances are employed that afford little resistance to slow flow of water but are adapted to develop turbulence and eddy currents opposing great resistance to high velocity flow of water. Preferably, also, t. ev are f such nature as to modify the subdivision and flow of steam with the water the surface tension of the water in contact with the steam, being an important factor. In F 1 to at inclusive, the flow resistan"ev means consists of a wire 21 having mounted there on an open. spiral of smaller wire 22, the composite structure being inserted 1 the tube 16, preferably loosely, and resting on the bottom of the lower tank.

In Figs. 5 and 6 the flow resistance is of relatively large wire 22 coiled in an. open helix instead of being mounted on a central Wire as in Fig. 3.

In Figs. 7 and 8 it iscorrugatcd or reversely bent ribbon, as 22*.

In Fig. 9, it is a tube 22 of somewhat smaller diameter than the tube 16, resting on the bottom of the tank and having its lower end cut away as at 24t to permit water circulation therethrough, instead of being a solid rod as in Fig. 3. i

In 10 the flow resistance is afforded by abrupt bends in the tube itself.

All of these flow resistance devices extend throughout the region of possible steam condensation in the tubes and constitute uniformly distributed flow resistances. llhey are preferably applied in. all of the tubes and will exercise their dc ed flow resistance with respect to water and subdividing effect with respect to steam bubbles, regardless of whether the circulation is up in some tubes and down in others or is upflowbf steam and downflow of condensate in each of the tubes.

In order to understand more fully the specific operations of the various flow resistances, it is necessary to consider more fully the conditions in operation of the unobstructed tubes.

Standard equipment radiators of the automobile type vary so widely in construction and proportion and, when operatedv for upflow cooling of water-carrying steam and steam-carrying water, the conditions are so widely variable, that detailed consideration of the functioning under any one condition is likely to be misleading, but for general application of my invention, it may e well. to note the following dii'liculties that I have discovered and solved:

For instance, the length of a tube may be to 100 times its diameter. In a typical case a straight cylindrical tube,say, 20 inches high by one-quarter inch diameter will have a flow section of only about one-twentieth of a square inch, so that its total cubic content is about l cubic inch. Consequently, if as much mic-quarter of a cubic inch of steam is given opportunity to enter the tube as a single body, without being subdivided into further bubbles by surface tension plus depth pressure, it will till about 5 inches of the tube; one-half cubic inch will fill 10 inches of the tube, etc. In the tube, such body or bubble of steam, whatever its length, will be subject to the above describes dominantpressure from below and the opposing static pressure of the water above. Surface tension tends to make its top and bottom surfaces spherical and it will tend to assume the form of a cylin drical piston with its cylindrical surfaces exposed to the cmd. walls of the tube. The details of what will happen thereafter either to the condensate or the bubble as the water flowsupward in the tube, need not be followed further than to explain that in its final stage of cooling and condensing, the body of steam collapses and the water rushes into the vacuum at high velocity, being impelled by both atn'iospheric and depth pressures. The resulting uncushioned head-on collision in the tube between columns of in compressible water, produces violent shock or water hammer eilect which the thin radiator walls effectively apply to the air as cracking and banging noises. This may be also accompanied by violent surgings of the water in ti o upper chamber resulting in e:' cessive losses through the overliow pipe.

Under certain. con ions the above opera.-

tions occur, in repeating cycles, the inflow of steam being by high velocity up rush intermittently out off by up-rush of water, and the resulting noises and surgings are of practically and commercially prohibitive violence.

On the other hand, smaller bubbles are less piston-like and the surrounding coiulensate affords them better protection from the walls of the cooling tubes. Furthermore, if the bubbles are small enough, the i use of their collapse'will be unnot'ceable and large number of them occurring continuously in the same tube, there will be little or no surging.

In this situation, it will be obvious that the above described flowbaflling devices are of such a character that th afford small opposition to normal, relati y low speed circulation, but atlori practicall prohibitive resistance against high speed v of water such as can produce objectionable noise effects in the tubes when considerable bodies of steam collapse therein. Such flowbaiiling devices have also an important hundred-tbs inch in diameter,

iiow section is about g o'l lll of a square inch,

that the diameter of the straight wire rod, 21, 1s,say, l0 hundredths and that of the helical winding wir 22 about 5 hundredths e of an inch. lhe straight wire 22 restricts the flow section only about one fourth but the smallest bubble that can enter the tube withoutbeing deformed is reduced from one-quarter inch down to one-sixteenth inch. Therefore, surface tension and depth pres sure will tend to cut large bubbles into bubbles of proportionally smaller size. The helical winding 22 doubles the projected diameter of the obstruction afforded by wire 21, the composite over all diameter being 20 hundredths as against 25 hundredths for the tubeadiameter ratio of l to 5, a projected area ratio of 16 to 25, or, roughly, 3 to 5. That is to say, geol'nctrically considered, two-fifths of the area remains unobstructed even for straight line iiow parallel with the axis of the tube, while an additional flow section is available by following the spiral. For slow flow of water these paths are practically free, just I as they seem, but for high velocity flow everything is vastly different] Straight longitudinal flow through the free two-fifths annulus, is bafiled every quarter inch by the eddy inducing wires 22 and by the conflicting [low that tries to flow in the helix but tends to be projected therefrom by centrifugal force. The water is thus caused to obstruct its own flow and the obstructing interference effects increase disproportionately with increasing velocities, at such a rapid rate, that extensive surgings or water hammer effects become impossible. Fun thermore, such localized" short distance surgings as could occur, are calculated to atomize any steam bubbles that are not already so small that their surface tension powerfully resists further subdivision.

I have thus analyzed some features of the functioning of the device of 3 and 4 merely by way of illustration, and because said device is cheap to make and highly etiicient. The described construction and the assumed details are not essential except the absolute sizes of the steam bubbles and the volumes that can collaps are important, and may become too great where as parts arson too large a scale Figs. 8,

giving the flow resistance is a single wire 22, which for a quarter inch tube, 16, may be say, inch in diameter, but this wire 22 is coiled in an open helix without any central support. Viewed endwise, as in Fig. 6, it leaves the area for free axial flow at the centre only about one-quarter to one-fifth the total cross-section of the tube 16. In both the above devices there is low resistance for slow velocity flow of water with bailiing, eddy producing, and mixing obstruction for high velocities. ln both, high speed cork-screw flow in the helix will develop centrifugal force tending to cause an axial vortex in which steam is enveloped or a vacuum invaded as by an outside cylinder of whirling water broken by endwise moving water and eddies.

Figs. 7 and 8 are illustrative of the fact that a ribbon 532, of suitable width may be bent in forms which though non-helical, will cause the desired turbulence and eddying resistance to high speed flow.

In ig. 9, a tube 22 having an external dian'ieter zqiproximately three-quarters of the internal diameter of the tube 16, leaves an annulus or crescent for upfiow in the tube 16, which is about two-fifths of the total flow section of the tube. In this case there is no battling of the flow intern'iediate the ends of the tube, the increasing flow resistance to prevent high velocity movements beingmerely the friction and molecular adhesion of the water which, as is well known increases phenomenally with narrowness of the space between the adjacent wetted surfaces. in Fig. 9, the maximum annulus or, rather, crescentspace, at the top and bottom is th of an inch and midway of the tube said spec is annulus of one E -nd inch thickness. The above concerns tube 22" merely as a flow reducing obstruction and resistance, but it is more than that because, being hollow, it is capable of functioning as a down-fiow tube for return of condensate or down surging cool water, from the upper chamber, to the lower chamber. The beveling at 24- is to afford free outlet for such flow, or, under special conditions, inlet for reverse flow upward. In all of the above figures, the obstructions and bullies are. preferably of aluminum or good heat conducting metal of low specific gravity, aluminum and its alloys desirably embodyiu both qualities.

Similar flow resistance effects are obtainable without special forms a low resistance devices, by employing a honeycomb of the so-called cellular type, wherein the passages have Zigzag, or octagonal, or rectangular arrangement, so that high velocity flow therein is baflled by abrupt turns at short intervals.

Such a cellular honeycomb is schematically indicated in 10, wherein the core lUO llO

or honeycomb consists of tubes 25 in flattened or ribbon term, the width of each tube representing the entire thickness of the honeycomb which may be, say, 2 inches to 3 inches, so that is possible to flex them to the rectangular arrangement shown.

In actual practice, each upflow passage has 80 to 100 or more or these right angle deflections and they are only a quarter of an inch or so apart. Consequently, while oii'ering hardly more than simple friction ree to ordinary slow flow of water, high y flow of considerable columns of water such as will produce noise and water hammer effects is prevented by the right angle impacts at 26, 26, etc., every quarter inch oi the way, each impact causing obstructing turbulence and whirls in the water. Consequently, the water hammer tendency, in so tar as it has any effect, is more likely to cause further mining and subdividing of the steam bubbles than to produce objection.- alle noise in the tubes or surging in the upper. chamber. This is notwithstanding but rather because of the fact that such ribbon tubes may have thin passages, only to inch thick, in which a bubble of any size may contact with both walls.

' The specific nozzle arrangement shown in big; 1 has practical advantages for changing small radiators such as those on the well known Ford cars, from downflow water cooling, to upi'low steam cooling, the nozzle 13 being in this case rigidly positioned with respect to the venturi 13 by casting the parts integrally connected through a support which serves to anchor the discharge end of the device to the bottom of the radiator while the other end is formed as a coupling element which has the bottom ot'the radiator clamped between it and the fitting collar of discharge pipe 9.

As to all forms of my invention, it will be understood that it the cooling capacity be exceeded, as may be the case when a fan belt breaks, the system will continue operative, with more or less loss of steam and water until the water is substantially exhausted, the final stages of the operation being in accordance with the method specifically described in my said Patent No. 1,378,724.

In all forms, the disproportionate increase of resistance with great increase of velocity of the flow, whether the fluid be water or water mixed with steam, or only steam, opcrates to apply a back pressure, tending to equalize the speed of flow in all of the passages and for this reason it is desirable to apply similar distributed flow resistances to all of the cooling paths. In certain cases it may also be desirable to have all of the said paths of approximately the same length, or of the same over-all flow resistance, particularly where the object is to bring all of the passages into operation before any of them are over-taxed.

It is to be understood, however, that while I have illustrated the honeycomb tubes as being all of the same size, and of the same flow resistances, variations are possible, particularly that where an injector is used, the down-flow tubes may be much larger in size or oi? less flow resistance and correspondingly the space thus saved may be devoted to upflow tubes. The entire core may be upflow, the dewnl'low being through one or more large conduits outside the radiator.

I claim 1. An internal combustion engine having a water and steam cooling circuit serially inch ding a force leed pump supplying water to the jacket of the engine, an outlet discharging hot water and steam from the jacket into the lower chamber of an air cooled, water filled radiator of the upright type having a multiplicity of small diameter cooling passages of great radiating capacity connecting said lower chamber with an upper chamber, in combination with discharge means arranged to discharge water and the steam from the engine in a region of said body of water that is below and in proximity to the lower ends of said passages, and flow restricting elements extending throughout the steam condensing regions otsaid passages.

2. An internal combustion engine having a water and steam cooling circuit serially including a force teed pump supplying water to the jacket of the engine, an outlet dischargi g hot water and steam from the jacket into the lower chamber of an air cooled, water filled radiator of the upright type having a multiplicity of small diameter cooling passages of great radiating capacity connecting said lower chamber with an upper chamber, in combination with discharge means arranged to discharge water and the steam from the engine in a region of said body of water that is below and in proximity to the lower ends of said passages, and helical flow restricting elements disposed throughout the steam condensing regions of said passages.

a water and steam cooling circuit serially including a force feed pump supplying wziter to the jacket of the engine, an outlet discharging hot water and steam from the jacket into the lower chamber of an air cooled, water filled radiator of the upright type having a multiplicity of small diameter cooling passages of great radiating capacity connecting said lower chamber with an upper chamber, in combination with discharge means arranged to discharge water and the steam from the engine in a region of said body of water that is below and in proxo. An internal combustion engine having imity to the lower ends 01" said passages, and helical flow restricting elements disposed throughout the steam, condensing regions of said passages but arranged. to afford direct paths of flow parallel with the axis of each passa e.

4:. in internal combustion engine having a water and steam cooling circuit serially including a force feed pump supplying water to the jacket oi. the engine, an outlet discharging hot water and steam from the jacket into the lower chamber of an air cooled, water filled radiator of the upright type having a multiplicity of small diameter cooling passages of great radiating capacity connecting said lower chamber with an upper chamber, in combination with discharge means arranged'to discharge water and the steam from the engine in a region olsaid body of water that is below and in proximity to the lower ends of said passages, the

steam condensing portions of said passages being formed and arranged to battle flow therethrough, thereby opposing relatively small flow resistance to low velocity flow,

but adapted to set up great flow resistance in opposition to the high velocity flow in any of said passages.

,5. An internal combustion engine having a water and steam cooling circuit serially including a force teed pump supplying water to the jacket of the engine, an outlet discharging hot water and steam from the jacket into the lower chamber of an air cooled, water filled radiator of the uoright type-having a multiplicity of small diameter cooling passages of great radiating capacity connectingsaid lower chamber with an'upper chamber, in combination with discharge means arranged to discharge water and the steam from the engine in a region of said :body of water that is below and in proximity to the lower ends of said passages, the steam condensing portions oi said passages bemg formed and arranged to baflle cooled radiator-condensi1 flow therethrough, thereby opposing rela- 'tively small flow resistance to low velocity flow, but adapted to set up turbulence, eddying and great liow resistance in opposition to the high velocity flow in any of said passages.

6. A cooling system for internal combustion engines, comprising a water and steam cooling circuit serially including 'lorce feed pump supplying water to the jacket of the engine, an outlet for discharge of hot water and steam from. the jacket, an air 1g apparatus having cylindrical cooling tubes, some or: which have less cooling capacity than others; means for supplying steam to said tubes from said outlet; a chamber into which all of said paths have outlet; and flow restricting elements extendin g throughout the steam condensing regions oi each of said tubes, each element comprising an axial elementand an open helical element surrounding the tubes, each element comprising a still rod or wire with a wire of less diameter wound thereon as an open helix.

Signed at Plainiield, in the county of :Union and State of New Jersey this 9th day of August A. D. 1926.

SAMUEL W. RUSHMOHE. 

